Waterproofing Exterior Stone Walls

Waterproofing Exterior Stone Walls


Waterproofing Exterior Stone Walls


Providing a permanent solution to damp is a real headache for any homeowner, but is especially the case when it comes to older properties. Why is this? Well, to put simply, modern buildings are constructed with damp in mind, often using cavity walls to create a barrier between the exterior wall and interior wall. 


However, many older properties and some newer properties are built using a solid wall construction, which can create problems.



But why can solid wall construction lead to damp problems? The cavity wall was first introduced in the 19th century, originally developed to allow building materials to 'breathe' by creating a gap between two layers of brick that are tied together using metal. Solid wall construction buildings do not have this gap, comprising of a single skin exterior wall.


This single solid wall may allow rain to absorb into the building, which in turn creates damp. This type of damp is called 'penetrating damp' and occurs when wind driven rain penetrates the exterior wall of a building. Once in the substrate, the moisture travels through the capillaries right through to the interior side of the wall. 


So how do you prevent water from penetrating stones walls? The moisture must be prevented from penetrating the exterior wall.


However, contrary to popular beliefs, stone wall waterproofing sealers and sealants can have a terrible effect on older properties. They create a waterproof 'film' on the surface of the brick or stone masonry that prevents moisture from entering the exterior wall. However, this film traps moisture inside the property, which occurs in every day life, especially in kitchens and bathrooms.


As this moisture gets trapped, surfaces begin to break down and large interior damp patches appear, leading to significant deterioration in building's integrity and causing irreparable damage.


So, what is the solution? You must use a stone waterproofing product that has an SD value of below 1. If a waterproof coating does not have an SD value of 1 or lower, this will not sufficiently allow water vapour to easily pass through the wall and escape.




The ideal technology for waterproofing stone walls is a highly breathable masonry protection cream. They create an invisible barrier on exterior walls that repels water, while remaining highly breathable. It is crucial to avoid any product that refers to itself as a sealer, as these products are often the less advanced film building waterproofers.


In the case of an advanced masonry protection cream, these products chemically bond to the stone wall, giving the stone itself waterproofing properties rather than simply creating a waterproof layer on the surface. 


By forming a part of the material, it does not negatively affect the breathability. It lines the pours of the material without sealing them completely, meaning it repels water from outside while still allowing moisture from inside to escape.

In an independent test, conducted by UKAS accredited laboratory Lucideon, Emperor Masonry Creme was tested in an accelerated 25-year weathering test.


The results of the tests demonstrated that Emperor Masonry Creme:


  • Reduced water absorption by 96.3%
  • On average to keep houses 6°C warmer compared to not treated properties
  • Maintained excellent breathability with SD values of 0.56, while a non-treated wall had an SD value 0.57


Waterproofing walls


25+ Year Performance


The 25-year accelerated weathering test also demonstrated that the waterproofing treatment showed no signs of deterioration in performance or change in aesthetic after the test was completed.


This meant that not only was the treatment just as effective after a 25-year period at regulating moisture levels, but the appearance of the exterior walls were preserved in the same state they were before the test was conducted. This is one of the most significant benefits of Emperor Masonry Creme for any property, but especially in the context of older properties. 


The treatment is clear, showing no form of film or shine once applied. As water is repelled off the waterproofed surface, so is dirt. Any dirt simply falls straight off with rain, leaving the stone always looking pristine. Furthermore, moss and other green growth is significantly reduced as moisture is the key driver of this growth.


The masonry cream acts as an exterior wall preserver, which is extremely important when maintaining the beauty of an aging property. A coating of Emperor Masonry Creme and a building can withstand extreme weather conditions for years to come.


Super hydrophobic


Heat Retaining


Moisture is one of the biggest causes of heat loss in properties. Wet walls act as a thermal bridge, helping heat to transfer out of a homemuch quicker than a dry wall. 


The masonry cream by limiting the moisture in buildings is heat retaining. The Lucideon tests showed that the wall treated with Emperor Masonry Creme stayed 6°C warmer on average than a non-treated wall.


This is why Emperor Paint products are verified by the Energy Saving Trust following their independent review process.


Emperor Heat Retaining Paint


We hope that this article has answered some of your questions regarding waterproofing exterior stone walls. Our team of experts are on hand to help you with any questions you may have as we know it can be a daunting task. If you would like to talk to one of the team, give them a ring on 0161 509 9009 or send an email to info@emperorpaint.co.ukIf you would like to waterproof your exterior walls using the most advanced technology available in the UK, shop our Emperor Masonry Creme today.